Walt, Aren't these some of Bob, N4HY's comments and what he was experimenting with at the time? At one time TAPR seemed to be one of the best sources of information and experimentation with new digital modes, especially on HF. The impression that I got was that things did not progress further in HF directions and this may have been the tail end of that time period. I can't even remember the time line and when I used to be a member. At the time, I found it very exciting with new HF developments. Then there appeared to be a shift toward VHF and higher frequencies and the satellites, APRS, etc.
Some day it would be really neat if someone could put up a timeline on many of the developments over the years and what did and what did not work out so that we could get a better understanding of the unfoldment of these developments. It is usually one person coming up with something that is a breakthrough and then eventually someone else taking it a bit further along with some other clever designs and coming up with something new. That is what Pactor did, by optimizing a little here and a little there and having something that worked pretty well. Unfortunately, it is single sourced and proprietary. I am sure that many of the early developers had to go out and make a living and just could not donate that much time to unpaid work and that might also at least partially explain why things move in ebb and flow at times. At least with the internet, the cycles of advancement are much, much faster than in the "old days" where it might take decades for the next advance to come forward. As you can see in the below information, there was a lot of interest in Linux and GPL software, much more in the tradition of amateur radio. Can someone fill us in further? 73, Rick, KV9U DuBose Walt Civ AETC CONS/LGCA wrote: >Here are some edited E-Mail threads from 1999 concerning HF digital >modems/modes. The names and/or calls deleted. > >So where are we in relations to Aug 1999 in reaching the goal of an open >source, high-speed, robust modem/mode using a sound card or some other COTS >hardware? > >73, > >Walt/K5YFW > >===================================================================================== > >I have just gotten working a software implementation of > >Mil. Std. 188-110-A1 modem using Soundblaster cards >and linux machines. You must have a linux sound >system driver (using /dev/dsp) in order for this >to work. It works in all modes, all speeds. >(75 bps-4800 bps, short and long interleavers), >it has a mode that is not in the mil-std that is >suitable for AX.25 and is an emulation but not a copy >of the Rohde & Schwarz modifications to the Mil >Std. and used in the their products. They >use R&S-HDLC, I will use HDLC and the AX.25 >system in linux. This is NOT compatible with their >stuff because I don't want to fool with their proprietary >stuff but uses some of their approaches. > >I will unleash it at the ARRL/TAPR DCC: > >http://www.tapr.org/dcc > >and there will be a paper in the proceedings with all of >the hairy gory details. > >It will be distributed with a Gnu P.L. It is based on >new work done by me extending work done by Nikias, >et. al. on using the EM algorithm to do simultaneous >channel parameter estimation and data estimation >in a near optimal fashion. This escapes the Harris >patent since it is not an equalizer at all. It makes >no attempt to equalize. For those unfamiliar with the >EM algorithm, I will give a good bibliography in the >proceedings paper. The EM algorithm was invented >and proven to work at the place I work in the mid >60's but is still drifting into widespread usage even >after Bell Labs made such a big fuss over it in >Rabiner's shop. > >The last trick after getting symbol probabilities out of >the channel in a great fashion, is decoding. The >code makes extensive use of these probabilities and >the signal structure (8 psk, Grey coded, etc.) to >estimate soft decisions on the bits which are then >permuted back to the original order (deinterleaved) >and fed into the ka9q decoder (thanks Phil!). > >It easily runs real time on a 100 Mhz linux pentium. >On my dec alpha, running on a file, it can demod >203 second transmission in 9 seconds. > >I will support anyone who wishes to port it to Windoze >and I have the Visual development tools to help, I >just don't want to learn directX, at this time (though >my kids do). I will start giving it away on the TAPR >site after I finish three things: > >(1) Cleaning up my mess so that others can read it. >(2) Fixing the performance of the "cut-in" demanded by the standard >(3) Making an implementation improvement in the correlation for > known symbols and their use in frequency offset calculations. > >See you in Phoenix. > >[name] > > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 2 02:56:52 1999 >[name] wrote: > >Congrats! This seems to be a big thing. We now have to possibility to >use a proven and good working system for amateur radio use (and not have >to use less capable and propriety systems like Pactor II or Clover). >Maybe this will lead to some mailbox store & forward to be done on >amateur radio HF and not on internet ... > > > > >>and there will be a paper in the proceedings with all of >>the hairy gory details. >> >>It will be distributed with a Gnu P.L. It is based on >>new work done by me extending work done by Nikias, >>et. al. on using the EM algorithm to do simultaneous >>channel parameter estimation and data estimation >>in a near optimal fashion. This escapes the Harris >> >> > >So you used the idea of doing the channel parameter estimation using >near ML algorithms... > > >Is it possible to get the paper online? I will not have the time (and >money) to join the DCC. > >About AX.25: [name] [call] [email address] is >currently reworking the kernel AX.25 and has done a quite capable AX.25 >to TCP/IP coupler with protocol booster, that might be well suited for >the bad HF channel. Have a look at >http://dl0td.afthd.tu-darmstadt.de/~dg2fef/ax25/features.html > >73´ [name] > > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 2 08:58:15 1999 > > >>[name] wrote: >> >> >>So you used the idea of doing the channel parameter estimation using >>near ML algorithms... >> >> > >Yes, the total likelihood is approximated. It will produced better >results than equalization (I have tested this more times than >I can count ;-)! ). and the algorithm is much cheaper than >the viterbi algorithm, which it most resembles. However, >it does both forwards and backwards and computes the >a posteriori conditional probabilities of the data symbols >given all of the observations. In our case, since there are >probes (known data) transmitted in every case but 75 bps, >this calculation is restricted to the region from one set of >probes to the next and then reestimation of the parameters >is done as mentioned. > > > >>Is it possible to get the paper online? I will not have the time (and >>money) to join the DCC. >> >> > >I will include the paper in the tgz and zip file I put in the TAPR ftp site >after I am done. My note is a little preliminary in that I will most >likely not put it up before the conference. I wanted people to know >that I would be doing it at the conference in case someone might >then decide to go because of this and it takes time to go to >one of these things. > >[name] > > > >>About AX.25: [name] [call] [email address] is >>currently reworking the kernel AX.25 and has done a quite capable AX.25 >>to TCP/IP coupler with protocol booster, that might be well suited for >>the bad HF channel. Have a look at >>http://dl0td.afthd.tu-darmstadt.de/~dg2fef/ax25/features.html >> >> > >Thanks for the tip. I run linux 2.2.10 (I just survived my first >kernel rebuild). His work is a little preliminary for me to use >since he has broken a bunch of the most popular of the >utilities but it is very interesting. > > > > >>73´ [name] >> >>-- >> >> >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 2 10:23:38 1999 >[name] wrote: > > > >>likely not put it up before the conference. I wanted people to know >>that I would be doing it at the conference in case someone might >>then decide to go because of this and it takes time to go to >>one of these things. >> >> > >Hello[name], > >I would like to add my congratulations, I will be very interested in >hearing your presentation, I might even get some fresh ideas for the >Stanag 4529 code I am working on (if I can understand your talk). > >For the information of others. >I emailed my paper to the ARRL on my digital voice system last friday, so >hopefully that should appear in the proceedings. I was thinking of doing >another one on my Win95 ALE controller but that can keep for another time. > >- [name] [call] > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 2 10:29:54 1999 > >Hi Folks, > >There you have it ... seems like HF digital topics will be >hot at the upcoming DCC. > >I have a fairly heavy paper on HF channel simulation for the SHARC >DSP EVM that I already submitted. Also planning on showing off a pair >of "new" Motorola 56K-based HF modems working through the >SHARC channel simulator. > >If things work out, and there is a time slot available, I have >an introductory presentation on the new modes: PSK31, CBPSK, >MTHELL, MT63, and digital voice. > >[name], [call], are planning on being there too and we might >see his voice over HF digital being demo'ed. > >[first name] [last name] plans on presenting a heavy-duty bit of work on a MIL >STD >modem that runs on Linux. That would be an interesting one to watch. > >TAPR is busy putting together a very worthwhile program for >the DCC, so plan on attending -- this one will be worth it. > >73 > >[name] [call] > > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 2 19:49:01 1999 > >PLEASE, be my guest and add Stanag versions of this to the code and I >will be most supportive. It will require you to implement the convolutional >deinterleaver and modify the size of the probe/data regions and then add >a few more cases ;-) to the decoding algorithms. I will look forward to >having you work on it. Even if you don't understand the maths, forget that, >understand the purpose of the blocks of code and you will be able to add >the Stanag modems to this easily. I just haven't bothered yet. > >[name] > > >At 04:15 PM 8/2/99 +0100, you wrote: > > >>[name] wrote: >> >> >> >>>likely not put it up before the conference. I wanted people to know >>>that I would be doing it at the conference in case someone might >>>then decide to go because of this and it takes time to go to >>>one of these things. >>> >>> >>Hello [name], >> >>I would like to add my congratulations, I will be very interested in >>hearing your presentation, I might even get some fresh ideas for the >>Stanag 4529 code I am working on (if I can understand your talk). >> >>For the information of others. >>I emailed my paper to the ARRL on my digital voice system last friday, so >>hopefully that should appear in the proceedings. I was thinking of doing >>another one on my Win95 ALE controller but that can keep for another time. >> >>- [name] [call] >> >>--- >>You are currently subscribed to hfsig as: >>To unsubscribe send a blank email to [EMAIL PROTECTED] >> >> > > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Tue Aug 3 02:42:50 1999 > >[name] wrote: > > >>PLEASE, be my guest and add Stanag versions of this to the code and I >> >> > >Hello[name], > >I have written my code in a fairly modular fashion, so it should not be too >difficult >to cut and paste it into your stuff. My copy of the Stanag is a bit smudged >and the page >describing the convolutional interleaver is almost unreadable, but I think I >have managed >to implement it ok. It certainly interleaves/deinterleaves fine. Suprisingly >all the text books >I have mention convolutional interleavers, they then all go on to describe >block interleavers! > >My intentions were to produce a Windows DLL so that other people can simply >integrate it >into their own code. All the windows sound handling stuff is already in there, >I have >used waveIn and waveOut calls rather than DirectX, I think the wave stuff is >being >deprecated by Microsoft, but I really can't be bothered to wade through all >the Microsoft >documentation to figure out how to use Direct Sound. > >- [name] > > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > >[name] wrote: > > > >>used waveIn and waveOut calls rather than DirectX, I think the wave stuff is >>being >>deprecated by Microsoft, but I really can't be bothered to wade through all >>the Microsoft >>documentation to figure out how to use Direct Sound. >> >> > >The problem IMO with DirectX is that there seem to be no full duplex capable >DX drivers (waveIO seems to be full duplex capable...) I've tried with several >soundcards that can do fullduplex under Linux, none of them could under >Windows/DirectX6.1 (I've tried a CS4236 card, and 2 SB PCI models). > >If anyone has found a DirectX full duplex capable soundcards (you can try this >eg. with FDFILTER.EXE from the DirectX SDK), please speak up. > > > >>My intentions were to produce a Windows DLL so that other people can simply >>integrate it >>into their own code. All the windows sound handling stuff is already in >>there, I have >> >> > >I've got some (DirectX) cross compilation stuff, that might make it easy >to produce both a Win32 DLL and Linux binaries. It uses GNU autoconf/automake. > >[name] > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Tue Aug 3 08:27:45 1999 >[First name] Last name] wrote: > > >> [First name] Last name] wrote: >> >>The problem IMO with DirectX is that there seem to be no full duplex capable >>DX drivers (waveIO seems to be full duplex capable...) I've tried with several >>soundcards that can do fullduplex under Linux, none of them could under >>Windows/DirectX6.1 (I've tried a CS4236 card, and 2 SB PCI models). >> >> >> > >Thats interesting [name], maybe I will stick with waveIO. I can do fullduplex >but like everying windows you have to be very careful. Its not re-entrant, so >you >can't make wave calls from the wave call-back procedures and some calls that >fail can >cause exceptions. For example I tried setting a 16/8 bit card to full duplex >16/16 >naturally it failed when I tried to open the second channel. Not only did it >fail >but crashed the OS as well! Another good one is trying to unprepare headers >that have not been >pepared, the docs say it should return a failure code, what in fact happens is >that the Kernel >also reports a memory exception. > > > >>I've got some (DirectX) cross compilation stuff, that might make it easy >>to produce both a Win32 DLL and Linux binaries. It uses GNU autoconf/automake. >> >> > >I have arranged my sound stuff to look a bit like a unix block io device. :-) > >- [name] > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Tue Aug 3 10:24:01 1999 >I understand your feelings completely. That is the very reason I >decided to do it first time on a linux box. While there have been >hassles with all of the competing factions vying for control of >the sound devices (enlightenment sound daemon being the >worst one yet), it is absolutely trivial to program the sound card. >And what is with this Stanag description anyway? It took me >a while to figure it out and then I said, later! Just a clever >way to get you decoding a bit faster through the interleaver >and probably not necessary but . . . . > >The rest of the code outside the sound stuff however is a bit >more difficult ;-). > >My code is exceedingly modular. I have gone from writing >single routine state machines (holdover from my assembly >and early dsp days) to subroutine based modularized code. >When you get to tens of thousands of lines of code, it >pretty much demands it. > >[name] > > > >At 08:34 AM 8/3/99 +0100, you wrote: > > >>[name] wrote: >> >> >>>PLEASE, be my guest and add Stanag versions of this to the code and I >>> >>> >>Hello [name], >> >>I have written my code in a fairly modular fashion, so it should not be too >>difficult >>to cut and paste it into your stuff. My copy of the Stanag is a bit smudged >>and the page >>describing the convolutional interleaver is almost unreadable, but I think I >>have managed >>to implement it ok. It certainly interleaves/deinterleaves fine. Suprisingly >>all the text books >>I have mention convolutional interleavers, they then all go on to describe >>block interleavers! >> >>My intentions were to produce a Windows DLL so that other people can simply >>integrate it >>into their own code. All the windows sound handling stuff is already in >>there, I have >>used waveIn and waveOut calls rather than DirectX, I think the wave stuff is >>being >>deprecated by Microsoft, but I really can't be bothered to wade through all >>the Microsoft >>documentation to figure out how to use Direct Sound. >> >>- [name] >> >> >> >> > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Wed Aug 4 16:31:55 1999 > >I have somewhat updated the PSK31 homepage. > >- I have added 2 interesting pages by Volker DH7UAF in German about PSK31SBW >and MixW32 in links page. >- I have added a pointer to Nick UT2UZ Homepage. >- I have added a full blown indexed search for the whole PSK31 Mailing list >archive, it's available from the mailing list page or directly at: > >http://aintel.bi.ehu.es/psk31listsearch.html > >- I have added a Word for Windows .doc file that contains the PSK31SBW > helpfile in Italian by Eduardo Alcolado I5PAC, that has been supplied by >Antonio Alcolado EA1MV mailto:[EMAIL PROTECTED] . If somebody is willing to >convert it in .HLP format this would be fine. The file is at: > >ftp://det.bi.ehu.es/pub/ham/psk31/p31sbw106doc-it.zip or >http://www.kender.es/~edu/download/p31sbw106doc-it.zip > > - I have also automated the subscribing process, now, it's a 2 step > process, you send a message for subscribing, majordomo sends you a message > that you have to succesfully receive and reply. > > Hope you will like it. > > [name]/[call] > >--- >You are currently subscribed to hfsig as: [EMAIL PROTECTED] >To unsubscribe send a blank email to [EMAIL PROTECTED] > > >>From [EMAIL PROTECTED] Mon Aug 9 22:47:28 1999 >Hi all, > >I wonder if there is a kind soul that may be so kind to help me >locate a copy of a paper. Our library stopped carrying this journal >in 1965! > >Title is: >L. Vogel and J. Hoffmeyer. A model for wideband HF propagation channels. >Radio Science 28(6):1131-1142, Nov. 1993. > >Apparently another approach for wide band HF channel simulation. >Is somewhat similar to the Watterson model for narrow-band channels, >but different distributions thus not quite Rayleigh in nature. > >Thanks very much in advance. > >73, > >[name], [call] > > > Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/digitalradio/join (Yahoo! 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